public class MixSum{
	public static void main(String args[]){
		int sum=0,a=0;
		for(int i=1;i<=100;i++){
			if(i%2==0){
				a=-(i*10+3);
			}else{
				a=i*10+3;
			}
			sum+=a;
		}
		System.out.println("sum is :" + sum);
	}
}